Configuring NBAR Using the MQC

First Published: April 4, 2006

Last Updated: August 7, 2008

After you enable Protocol Discovery, you can configure Network-Based Application Recognition (NBAR) using the functionality of the Modular Quality of Service (QoS) Command-Line Interface (CLI) (MQC). The MQC uses traffic classes and traffic policies (policy maps) to apply QoS features to classes of traffic and applications recognized by NBAR.

This module contains concepts and tasks for configuring NBAR using the MQC.

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Your Cisco IOS software release may not support all of the features documented in this module.For the latest feature information and caveats, see the release notes for your platform and software release. To reach links to specific feature documentation in this module and to see a list of the releases in which each feature is supported, use the "Feature Information for Configuring NBAR Using the MQC" section.

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Information About Configuring NBAR Using the MQC

NBAR and the MQC Functionality

To configure NBAR using the MQC, you must define a traffic class, configure a traffic policy (policy map), and then attach that traffic policy to the appropriate interface. These three tasks can be accomplished by using the MQC. The MQC is a command-line interface that allows you to define traffic classes, create and configure traffic policies (policy maps), and then attach these traffic policies to interfaces.

In the MQC, the class-map command is used to define a traffic class (which is then associated with a traffic policy). The purpose of a traffic class is to classify traffic.

Using the MQC to configure NBAR consists of the following:

•Defining a traffic class with the class-map command.

•Creating a traffic policy by associating the traffic class with one or more QoS features (using the policy-map command).

•Attaching the traffic policy to the interface with the service-policy command.

A traffic class contains three major elements: a name, one or more match commands, and, if more than one match command exists in the traffic class, an instruction on how to evaluate these match commands (that is, match-all or match-any). The traffic class is named in the class-map command line; for example, if you enter the class-map cisco command while configuring the traffic class in the CLI, the traffic class would be named "cisco."

The match commands are used to specify various criteria for classifying packets. Packets are checked to determine whether they match the criteria specified in the match commands. If a packet matches the specified criteria, that packet is considered a member of the class and is forwarded according to the QoS specifications set in the traffic policy. Packets that fail to meet any of the matching criteria are classified as members of the default traffic class.

NBAR and the match protocol Commands

NBAR recognizes specific network protocols and network applications that are used in your network. Once a protocol or application is recognized by NBAR, you can use the MQC to group the packets associated with those protocols or applications into classes. These classes are grouped on the basis of whether the packets conform to certain criteria.

For NBAR, the criterion is whether the packet matches a specific protocol or application known to NBAR. Using the MQC, network traffic with one network protocol (citrix, for example) can be placed into one traffic class, while traffic that matches a different network protocol (gnutella, for example) can be placed into another traffic class. Later, the network traffic within each class can be given the appropriate QoS treatment by using a traffic policy (policy map).

You specify the criteria used to classify traffic by using a match protocol command. Table 1 lists some of the available match protocol commands and the corresponding protocol or traffic type recognized and supported by NBAR.

Configuring a Traffic Class

Traffic classes can be used to organize packets into groups based on a user-specified criteria. For example, traffic classes can be configured to match packets on the basis of the protocol type or application recognized by NBAR. In this task, the traffic class is configured to match on the basis of the Citrix protocol type.

Note The match protocol citrix command is shown in Step 4. The match protocol citrix command is just an example of one of the match protocol commands that can be used. For a complete list of match protocol commands, see the command documentation for the Cisco IOS release that you are using.

To configure a traffic class, perform the following steps.

Restrictions

Typically, a single traffic class contains one or more match commands that can be used to organize packets into groups on the basis of a protocol type or application. You can create as many traffic classes as needed. However, for Cisco IOS Release 12.2(18)ZY, the following restrictions apply:

•A single traffic class can be configured to match a maximum of 8 protocols or applications.

•Multiple traffic classes can be configured to match a cumulative maximum of 95 protocols or applications.

SUMMARY STEPS

1. enable

2. configureterminal

3. class-map [match-all | match-any] class-map-name

4. match protocol citrix

5. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

•Enter your password if prompted.

Step 2

configureterminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

class-map [match-all | match-any] class-map-name

Example:

Router(config)# class-map cmap1

Creates a class map to be used for matching packets to a specified class and enters class-map configuration mode.

•Enter the name of the class map.

Step 4

match protocol citrix

Example:

Router(config-cmap)# match protocol citrix

Configures NBAR to match Citrix traffic.

Note The match protocol citrix command is just an example of one of the match protocol commands that can be used. For a complete list of match protocol commands, see the command documentation for the Cisco IOS release that you are using.

Note For Cisco IOS Release 12.2(18)ZY, a maximum of 8 match protocol commands can be configured in a single traffic class.

Step 5

end

Example:

Router(config-cmap)# end

(Optional) Returns to privileged EXEC mode.

Configuring a Traffic Policy

Traffic that matches a user-specified criterion can be organized into a specific class that can, in turn, receive specific user-defined QoS treatment when that class is included in a policy map.

To configure a traffic policy, perform the following steps.

Note The bandwidth command is shown in Step 5. The bandwidth command configures the QoS feature class-based weighted fair queuing (CBWFQ). CBWFQ is just an example of a QoS feature that can be configured. Use the appropriate command for the QoS feature that you want to use.

As of Cisco IOS Release 12.2(18)ZY, CBWFQ is not supported on the Catalyst 6500 series switch that is equipped with a Supervisor 32/programmable intelligent services accelerator (PISA).

Restrictions

For Cisco IOS Release 12.2(18)ZY, an existing traffic policy (policy map) cannot be modified if the traffic policy is already attached to the interface. To remove the policy map from the interface, use the no form of the service-policy command.

(Optional) Specifies or modifies the bandwidth allocated for a class belonging to a policy map.

•Enter the amount of bandwidth as a number of kbps, a relative percentage of bandwidth, or an absolute amount of bandwidth.

Note The bandwidth command configures the QoS feature class-based weighted fair queuing (CBWFQ). CBWFQ is just an example of a QoS feature that can be configured. Use the appropriate command for the QoS feature that you want to use.

Note As of Cisco IOS Release 12.2(18)ZY, CBWFQ is not supported on the Catalyst 6500 series switch that is equipped with a Supervisor 32/PISA.

Step 6

end

Example:

Router(config-pmap-c)# end

(Optional) Returns to privileged EXEC mode.

Attaching a Traffic Policy to an Interface or Subinterface

After a policy map is created, the next step is to attach the traffic policy (sometimes called a policy map) to an interface or subinterface. Traffic policies can be attached to either the input or output direction of the interface or subinterface.

Note Depending on the needs of your network, you may need to attach the traffic policy to an ATM PVC, a Frame Relay data-link connection identifier (DLCI), or other type of interface.

To attach a traffic policy (policy map) to an interface, perform the following steps.

SUMMARY STEPS

1. enable

2. configureterminal

3. interfacetype number [name-tag]

4. pvc [name] vpi/vci [ilmi | qsaal | smds | l2transport]

5. exit

6. service-policy {input | output} policy-map-name

7. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

•Enter your password if prompted.

Step 2

configureterminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

interfacetype number [name-tag]

Example:

Router(config)# interface ethernet 2/4

Configures an interface type and enters interface configuration mode.

•Enter the interface type and the interface number.

Step 4

pvc [name] vpi/vci [ilmi | qsaal | smds | l2transport]

Example:

Router(config-if)# pvc cisco 0/16

(Optional) Creates or assigns a name to an ATM permanent virtual circuit (PVC), specifies the encapsulation type on an ATM PVC, and enters ATM virtual circuit configuration mode.

Note This step is required only if you are attaching the policy map to an ATM PVC. If you are not attaching the policy map to an ATM PVC, advance to Step 6.

Step 5

exit

Example:

Router(config-atm-vc)# exit

(Optional) Returns to interface configuration mode.

Note This step is required only if you are attaching the policy map to an ATM PVC and you completed Step 4. If you are not attaching the policy map to an ATM PVC, advance to Step 6.

Step 6

service-policy {input | output} policy-map-name

Example:

Router(config-if)# service-policy input policy1

Attaches a policy map (traffic policy) to an input or output interface.

•Specify either the input or output keyword, and enter the policy map name.

Note Policy maps can be configured on ingress or egress routers. They can also be attached in the input or output direction of an interface. The direction (input or output) and the router (ingress or egress) to which the policy map should be attached vary according your network configuration. When using the service-policy command to attach the policy map to an interface, be sure to choose the router and the interface direction that are appropriate for your network configuration.

Note After you use the service-policy command, you may see two messages similar to the following:

After you create the traffic classes and traffic policies (policy maps), you may want to verify that the end result is the one you intended. That is, you may want to verify whether your traffic is being classified correctly and whether it is receiving the QoS treatment as intended. You may also want to verify that the protocol-to-port mappings are correct.

To verify the NBAR traffic classes, traffic policies, and protocol-to-port mappings, perform the following steps.

SUMMARY STEPS

1. enable

2. show class-map [class-map-name]

3. show policy-map [policy-map]

4. show policy-map interfacetype number

5. show ip nbar port-map [protocol-name]

6. exit

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

•Enter your password if prompted.

Step 2

show class-map [class-map-name]

Example:

Router# show class-map

(Optional) Displays all class maps and their matching criteria.

•(Optional) Enter the name of a specific class map.

Step 3

show policy-map [policy-map]

Example:

Router# show policy-map

(Optional) Displays the configuration of all classes for a specified service policy map or all classes for all existing policy maps.

•(Optional) Enter the name of a specific policy map.

Step 4

show policy-map interfacetype number

Example:

Router# show policy-map interface Fastethernet 6/0

(Optional) Displays the packet and class statistics for all policy maps on the specified interface.

•Enter the interface type and the interface number.

Step 5

show ip nbar port-map [protocol-name]

Example:

Router# show ip nbar port-map

(Optional) Displays the current protocol-to-port mappings in use by NBAR.

Example: Configuring a Traffic Class

In the following example, a class called cmap1 has been configured. All traffic that matches the citrix protocol will be placed in the cmap1 class.

Router> enable

Router# configure terminal

Router(config)# class-map cmap1

Router(config-cmap)# match protocol citrix

Router(config-cmap)# end

Example: Configuring a Traffic Policy

In the following example, a traffic policy (policy map) called policy1 has been configured. Policy1 contains a class called class1, within which CBWFQ has been enabled.

Router> enable

Router# configure terminal

Router(config)# policy-map policy1

Router(config-pmap)# class class1

Router(config-pmap-c)# bandwidth percent 50

Router(config-pmap-c)# end

Note In the above example, the bandwidth command is used to enable Class-Based Weighted Fair Queuing (CBWFQ). CBWFQ is only an example of one QoS feature that can be applied in a policy map. Use the appropriate command for the QoS feature that you want to use.

As of Cisco IOS Release 12.2(18)ZY, CBWFQ is not supported on the Catalyst 6500 series switch that is equipped with a Supervisor 32/PISA.

Example: Attaching a Traffic Policy to an Interface or Subinterface

In the following example, the traffic policy (policy map) called policy1 has been attached to Ethernet interface 2/4 in the input direction of the interface.

Router> enable

Router# configure terminal

Router(config)# interface ethernet 2/4

Router(config-if)# service-policy input policy1

Router(config-if)# end

Example: Verifying the NBAR Protocol-to-Port Mappings

The following is sample output of the show ip nbar port-map command. This command displays the current protocol-to-port mappings in use by NBAR. Use the display to verify that these mappings are correct.

Router# show ip nbar port-map

port-map bgp udp 179

port-map bgp tcp 179

port-map cuseeme udp 7648 7649

port-map cuseeme tcp 7648 7649

port-map dhcp udp 67 68

port-map dhcp tcp 67 68

If the ip nbar port-map command has been used, the show ip nbar port-mapcommand displays the ports assigned to the protocol.

If the noip nbar port-map command has been used, the show ip nbar port-map command displays the default ports. To limit the display to a specific protocol, use the protocol-name argument of the show ip nbar port-map command.

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Feature Information for Configuring NBAR Using the MQC

Table 2 lists the features in this module and provides links to specific configuration information. Only features that were introduced or modified in Cisco IOS Release 12.2(1) or a later release appear in the table.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Note Table 2 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.

Table 2 Feature Information for Configuring NBAR Using the MQC

Feature Name

Releases

Feature Information

QoS: DirectConnect PDLM

12.4(4)T

Provides support for the DirectConnect protocol and Packet Description Language Module (PDLM). The DirectConnect protocol can now be recognized when using the MQC to classify traffic.

The following sections provide information about the QoS: DirectConnect PDLM feature:

Integrates NBAR and Firewall Service Module (FWSM) functionality on the Catalyst 6500 series switch that is equipped with a Supervisor 32/programmable intelligent services accelerator (PISA). Additional protocols are now recognized by NBAR.

Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R)

Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.